1. Technical Field
The present invention relates to an optically writable display medium and an optical writing method.
2. Related Art
In recent years, optically writable space modulation devices in which an optical switching element and a display element are combined have been developed and practically used as light bulbs in projectors for example.
The optically writable spatial modulation devices change the impedance of the optical switching element according to the amount of received light while applying a given voltage to an element, and controls the voltage applied to the display element to thereby drive the display element for displaying an image. In particular, detachable optically writable display media that use elements having memory properties as display controlling elements of the optically writable space modulation devices have attracted attention as electronic paper media.
As the display elements for the optically writable display media, for example, liquid crystal display elements, such as nematic liquid crystals, cholesteric liquid crystals, and ferroelectric liquid crystals that have been imparted with memory properties by being dispersed in polymers; electrophoretic elements; elements that utilizes rotation by electric field; elements that utilizes movement of toner by electric field; and elements obtained by encapsulating these elements have been studied.